Rail grinder

ABSTRACT

A GRINDING HEAD INCLUDING A ROTARY GRINDING WHEEL IS SUPPORTED FROM A VEHICLE FOR MOVEMENT ALONG AND IN GRINDING ENGAGEMENT WITH A RAIL. A PORTION ONLY OF THE WEIGHT OF THE GRINDING HEAD IS SUPPORTED FROM THE VEHICLE BY FLUID PRESSURE MEANS INCLUDING AN EXPANSIBLE CHAMBER THE VOLUME OF WHICH VARIES WITH VARIATIONS IN THE OPERATING LEVEL OF THE GRINDING HEAD. THE UNSUPPORTED WEIGHT OF THE GRINDING HEAD IS APPLIED AS OPERATIVE PRESSURE OF THE GRINDING WHEEL AGAINST THE RAIL. A PRESSURE CONTROL UNIT IN COMMUNICATION WITH THE EXPANSIBLE CHAMBER AUTOMATICALLY VARIES THE PRESSURE OF FLUID IN SUCH CHAMBER AS THE GRINDING HEAD DEVIATES FROM A PREDETERMINED OPERATING LEVEL TO ABRUPTLY INCREASE THE OPERATING PRESSURE AS THE GRINDING HEAD FALLS BELOW SAID LEVEL AND TO ABRUPTLY DECREASE SUCH PRESSURE AS THE GRINDING HEAD RISES ABOVE SUCH PREDETERMINED LEVEL.

Sept 21, 1971 A. RIVOIRE RAIL GRINDER Filed July 30, 1969 2 Sheets-Sheet1 e, m m v w A4 55W @VO/EE 4; (W Array/vars Sept. 21 1971 A. RIVOIRE3,606,705

RAIL GRINDER Filed July 30, 1969 2 Sheets-Sheet a PRESSURE .-;SOURCEQEGULNYOR W424, cwywa #21014 United States Patent Filed July 30, 1969,Ser. No. 845,952 Int. Cl. 1324b 23/00 U.S. Cl. 51-178 Claims ABSTRACT OFTHE DISCLOSURE A grinding head including a rotary grinding wheel issupported from a vehicle for movement along and in grinding engagementwith a rail. A portion only of the weight of the grinding head issupported from the vehicle by fluid pressure means including anexpansible chamber the volume of which varies with variations in theoperating level of the grinding head. The unsupported weight of thegrinding head is applied as operative pressure of the grinding wheelagainst the rail. A pressure control unit in communication with theexpansible chamber automatically varies the pressure of fluid in suchchamber as the grinding head deviates from a predetermined operatinglevel to abruptly increase the operating pressure as the grinding headfalls below said level and to abruptly decrease such pressure as thegrinding head rises above such predetermined level.

This invention relates to improvements in Rail Grinders of the generaltype exemplified in the Speno et al. U.S. Pats. Nos. 2,779,141, of Jan.29, 1957, and 3,358,406 of Dec. 19, 1967.

It is well known that through continued use over a period of time, therails in a usual railroad track become worn in such a way as to formlongitudinal waves or corrugations in the rail heads or portions thereofwhich are engaged by the train wheels. Where the amplitude of such wavesor, in other words, the distance along the rail be tween the adjoiningwave peaks, is greater than the diameters of the grinding wheels of therail grinder, the floatingly supported grinder heads will tend to riseand fall with the waves, and thus will grind away as much material inthe hollows between waves as on the peaks or crests of the waves,whereas it is desirable only to grind away the crests of the waves toachieve a level condition of the rail surfaces.

The above-mentioned Speno et al. Pat. No. 3,358,406 discloses acombination of a constant fluid pressure counterbalancing means for thefloating grinder heads, in combination with a separate variable rate orresilient counterbalancing means therefor, operating together toengagement pressure between a given grinding Wheel and a rail, as thegrinding wheel passes over a depression in the rail and to provideincreased pressure of the grinding wheel against the rail in passingover a raised portion thereof.

It is a primary object of the present invention to achieve these samefunctions and advantages but by a simplified mechanism eliminating theseparate resilient means and utilizing a novel fluid pressure actuatedand controlled floating suspension for each grinder head, in whichdeviation of the grinder head below or above a predetermined operationalposition will actuate a pressure control means for causing the fluidactuated suspension to support a greater or lesser constant proportionof the weight of the grinder head and thereby abruptly to decrease theefficiency 0f the grinding action as the wheel passes over the hollowsbetween waves and to abruptly increase the efficiency thereof and therate of removal of metal as the grinding wheel tends to be raised inpassing over the peaks of the waves. Such abrupt changes of operatingpressure of the grinding wheel to new constant operating pressures servemore nearly to achieve a truly level surface on the rail than ispossible where the deviation of the grinding wheel from its optimumoperating level is resiliently or progressively opposed as by springmeans or the like.

In order to promote an intelligent understanding of the invention, suchas will enable those of ordinary skill in the art to practice it, apreferred embodiment of the invention is illustrated in the accompanyingdrawings and described in detail hereinafter. It will be understood thatthe drawings are by way of illustration only, and that the invention isintended to encompass all of the different variations and modificationswhich should be obvious to those skilled in the art to which theinvention pertains.

Thus, in the accompanying drawings:

FIG. 1 is a general diagrammatic fragmentary side elevation of a vehicleequipped with the rail grinding equipment of the invention for grindingof the rails as the vehicle travels along them.

FIG. 2 is a fragmentary perspective view, on an enlarged scale, of asingle grinder head and its associated fluid suspension as employed inthe present invention.

FIG. 3 is a diagrammatic view of a single such grinder head and thefluid suspension system.

Referring now in detail to the accompanying drawings, the grindingmechanism of the invention is illustrated as including a car or vehicleV having flanged wheels 10 of conventional construction and arrangementby means of which it is supported and guided for movement along theparallel rails R of a conventional railroad track to grind the treadsurfaces of the rails and if desired, their side faces, for the purposeof removing therefrom various irregularities normally created by wearand to substantially regenerate the tread surface and/ or side faces torectilinear configuration longitudinally of the rails. The vehicle maybe substantially similar to that disclosed in the Speno et al. Pat.3,358,406.

Rigidly aflixed to and suspended beneath the frame of the vehicle V, area plurality of pairs of horizontal transversely extending cross-bars 12along which are adjustably disposed the longitudinally opposed slides14, respectively, supporting the longitudinally opposed and alignedbearing 16 within which are journalled the trunnions 18 of a cradle orsupport 20 for a grinder head G. The trunnions and bearings arelongitudinally aligned with the direction of movement of the vehiclealong the rails R to permit adjusting of the cradles and grinder headsabout the trunnions so that the track may be engaged and ground at anyof various angles of tilt. Each grinder head comprises a preferablyelectrically driven grinder motor 22 having a vertical depending outputshaft 24 at the lower end of which is carried a grinding wheel 26 ofconventional abrasive material arranged so that its axially presentedlower face is adapted for operative engagement with the rail Rtherebeneath.

The grinder head G is supported by the cradle 20 for tilting movementabout the trunnions 18 so that the grinding wheel thereof may becorrespondingly tilted (with respect to the rails to grind either thetop surface or side surfaces thereof as desired.

The three grinder heads G of the gang shown in FIG. 1 are individuallysupported from the vehicle V in longitudinal alignment with each otherover one of the rails R so that the grinding wheel of each grinder headG may operatively engage the surface of the rail head and may rise andfall with the Waves in the rail during passage thereover. For floatinglysuspending or supporting the grinder head, the casing of the motor hasafiixed thereto on opposite sides thereof the diametrically opposedcylinder 27 of a conventional fluid pressure means 28, here consistingof fluid actuated piston and cylinder units respectively definingexpansible chambers 31. It will be understood that the pistons 29 ofsuch units are fixedly supported within the cylinders at the upper endsof stationary piston rods 30, the lower ends of which are rigidlyaflixed to the cradle 20.

For maintaining each grinder head in its desired angular adjustmentabout the horizontal trunnions 18, there is aflixed to the cradle anupwardly projecting quadrant plate 32 formed with an arcuate slot 34concentric to the axis of the trunnions. An upwardly projecting leverarm 36 affixed to the cradle has a threaded stud 38 projecting andmovable through this slot, whereby a nut threaded on the outer end ofthe stud may be tightened into frictional engagement with the quadrantplate to fix and maintain the angular position of the cradle and grinderhead G.

Supplied into the expansible chamber 31 of each cylinder between thepiston 29 and the upper end thereof, as for instance through theconduits 42 shown in FIG. 3, is a suitable actuating fluid, such as oilor other hydraulic liquid which is normally at a pressure to supportonly a predetermined part of the weight of the grinder head less thanthe entirety thereof, the balance or unsupported portion of the weightserving to press the grinding wheel 26 downwardly into operativeengagement with the rail R therebeneath.

The construction and arrangement as thus far generally described isconventional and is similar to that disclosed in the Speno et al. Pat.No. 3,358,406 except that the resilient or variable ratecounter-balancing means of that patent are completely eliminated.

In accordance with the present invention, the fluid pres sure means 28for each grinder head is made to apply a varying supporting force to thegrinder head depending upon variations in the vertical position of thegrinder head from its intended level of operation. The arrangement issuch that as the grinder head G and its grinding wheel 26 descend belowthe predetermined level of operation, the fluid pressure means 28provides an increased supporting force to thus decrease the grinding orcutting action on the rail as the grinding wheel 26 passes over thehollows between waves. As the grinder head and wheel are raised inpassing over the peaks of the waves, the said fluid pressure meanssupports a lesser proportion of the weight of the grinder head, therebycausing the grinding wheel to press harder against the rail and removematerial therefrom at an increased rate.

For these purposes, the fluid supply line 42 which communicates with andcarries the pressurized fluid into the expansible chambers at the upperends of the piston and cylinder units 28, communicates, at times, with acompletely enclosed tank 44 containing a reservoir of oil or hydraulicfluid 46 in its lower portion, and above which is a cushion 48 ofpressurized air or gas. A conduit 50 places the upper end of the tankand the air cushion therein in communication through a conventionaladjustable pressure regulator 52 with the pressurized air supply,exemplified in part by the pipe section 54.

By regulating the pressure of air supplied into the upper portion of thetank 44, it is possible to impose a similar pressure on the liquid 46which is supplied into the upper ends of the piston and cylinder units,the pressure preferably being regulated to support a predeterminedportion only of the weight of the grinder head G, whereby the remainingweight thereof may serve to thrust the grinding wheel into operativeengagement with the rail.

For increasing the pressure of the fluid acting within the cylinders,responsive to downward movement of the grinding head from apredetermined level and for decreasing such pressure as the grindinghead moves upwardly above said level, there is provided a pressurecontrol unit in the form of a cylinder block 56 defining therein atwo-diameter pressure increasing cylinder 58 and a two-diameter pressurereducing cylinder 60. Differential pistons 62 and 64, respectively, areslidably disposed in the respective cylinders 58 and 60. Such pistonsnormally abut against stop means 66 and 68, which, in

4 the preferred embodiment, comprise the annular shoulders at thejuncture of the large and small diameter ends of each cylinder.

The upper ends of the cylinder or cylindrical chambers are in constantcommunication through a passage 70 and line 72 with the air pressureregulator 52 so that the pistons 62 and 64 within the respectivecylinders will be exposed at all times to the constant air pressuresupplied by said regulator. The lower ends or portions of the respectivedifferential cylinders communicate through the passage 74 and hydraulicline 76 with the hydraulic conduit 42 at a location of the latter whichis between the fiuid pressure means 23 and the tank 44. Also located inthe oil supply line between the tank 44 and the juncture of the line '76with the conduit 42 is an isolating valve 78, preferably of the solenoidcontrolled type, which may be closed to isolate the fluid pressure means28 and the lower ends of the cylinders of the control unit 56 from thetank 44 and the air pressure regulator, thereby entrapping apredetermined quantity of oil in the hydraulic units and lower chambersand their interconnecting lines or conduits. Thus when the solenoidvalve 78 is in its normal closed position, the conduit 42, line 76 andpassage 74 serve as a means for providing a normally closed path ofcommunication between each expansible chamber 31 and the lower ends ofcylinders 53 and 60.

It will be understood that each grinder head will have its own controlunit and system associated with its respective piston and cylinder unitsor fluid pressure means 28, whereby variations in the level of onegrinder head will not affect the position of another grinder head.Manifestly, the grinder heads, control units and associated parts may bethe same for each grinder head as is illustrated in FIG. 3.

OPERATION In the use of the invention, which is believed to be obviousfrom the foregoing description, the grinder heads G of a given gang willbe positioned over and in operative engagement with one of the rails Rwhich is being traversed by the vehicle V. The solenoid valve 78 isopened to permit communication between the tank 44 and the expansiblechambers 31 of the fiuid pressure means 28 of the grinding head. Theadjustable fluid pressure regulator 52 is adjusted to supply air to thetank 44 and thus transmit oil pressure to the expansible chambers 31 inan amount suflicient to support a portion only of the weight of thegrinder head, whereupon the latter will be lowered into engagement withthe rail to be ground. After each grinding head is lowered to bring itsgrinder wheel 26 to rest against the rail, the pressure regulator 52.for each grinder head is adjusted to cause the fluid cylinder andpiston units of the grinder head to support a desired proportion of theweight of the grinder head, so that the remaining unsupported weight maybe utilized to urge the grinding wheel into operative engagement withthe rail, at a pressure which is selected to secure an optimum grindingaction on the rail R, when the grinding wheel is at a predeterminedoperating level.

With the grinder head thus positioned at its predetermined operatinglevel, the solenoid valve 78 is then closed in obvious manner to isolatethe piston and cylinder units or fluid pressure means 28 and the lowerends of the two diameter cylinders 58 and 60 from the tank 44, therebyentrapping a predetermined volume of fluid in these parts and in theclosed path of communication between them, at a pressure equal to thatdischarged from the fluid pressure regulator. Thus, when the grinderhead is supported at its desired predetermined level, as abovedescribed, the pressure in the upper and lower ends of the two-diametercylinders 58 and 60 of the control unit will be equal. Accordingly, theequalized fluid pressures on opposite sides of the differential piston62 of cylinder 58 will force said piston downwardly and normallymaintain it in a position of rest with its larger diameter portion inabutment with the upwardly facing annular shoulder or stop means 66 atthe juncture of the different diameter portions of the cylinder. On theother hand, the equalized fluid pressures in the opposite ends of theother control cylinder 60 will exert a differential force urging andmaintaining the enlarged lower end of the differential piston 64 inabutting stationary position in engagement with the downwardly directedannular shoulder or stop means 68 at the junction of the different,diameter portions of the cylinder.

As the vehicle V with its several grinder heads G moves along the railR, as each grinding wheel 26 passes over a depressed portion of the railbetween wave crests, the ensuing downward movement of the grinder headwill force hydraulic fluid from the expansible chambers 31 back throughthe conduit 42, line 76 and passage 74 into the lower end of the controlcylinder 58. Such displaced fluid obviously will not affect thedifferential piston 64 since its enlarged lower end is already inabutment with the stop shoulder 68. However, such displaced fluid willraise the differential piston 62 from the stop shoulder 64 and urge itsenlarged upper end upwardly into the large diameter end of the controlcylinder 58. Though the pressure in the upper end of the cylinder willremain constant, being thus maintained by action of the regulator 52, itwill be apparent that, because of the differences in diameter betweenthe upper and lower portions of the differential piston 62 exposed tothe fluid pressure, a substantially greater fluid pressure is requiredin the lower end of the cylinder than in the upper end thereof toinitiate a raising or unseating of the piston from its stop means 66.During the upward displacement of the piston, the pressure which actsupon it in the upper end of the cylinder will be maintained constant byaction of the regulator 52, thereby to maintain a constant increasedfluid pressure in the lower end of the cylinder as long as the piston israised. Such increased constant fluid pressure is transmitted to theexpansible chambers 31 of the cylinder piston units and thus enablingthe same to support a greater proportion of the weight of the grinderhead than when the piston is in its normal seated position and therebyto decrease the grinding pressure of the grinding wheel on the rail.

On the other hand, when the grinding wheel 26 of each grinding head Gpasses over a raised portion of the rail, as for instance, in passingover the peak of a longitudinal wave therein, the resultant raising ofthe grinding head and its supporting cylinders with respect to thepistons therein, will enlarge the expansible chambers 31 to draw thehydraulic fluid from the enlarged lower end of the low pressureresponsive cylinder 60, thus reducing the pressure therein. Thedifferential piston 64 will accordingly move downwardly away from itsstop shoulder, being urged into engagement with the hydraulic fluid bythe constant air pressure maintained by the regulator in the upper endof the cylinder. The piston 62 will remain stationary, in engagementwith its stop means 66.'Because of the differences in area of therespective upper and lower ends of the differential piston 64, which areexposed to the fluid pressures within their respective cylinder ends, aslong as the piston 64 thus remains unseated from its stop shoulder '68,due to operation of the grinding wheel over a high portion or crest ofthe wave in a rail, a substantially decreased but constant portion ofthe weight of the grinder head will be supported by the fluid pressurewithin the expansible chambers 31, as will be readily apparent.-However, as soon as the grinding head G is restored to its predeterminedlevel of operation on the rail, the differential piston 64 will bereseated against its stop means 68 and thus will maintain the oil withinthe expansible chambers 31 at the upper end of the cylinders 27 at anormal pressure to support the desired and predetermined portion of theweight of the grinder head and thus to cause the same to exert thedesired operating pressure against the rail.

It is to be particularly noted that the action of the invention is suchthat, when a grinding wheel deviates in either direction from itspredetermined level of operation, the resulting pressure change withinits associated expansible chambers is in the form of an abrupt shift toa constant higher or lower pressure, this serving more nearly to achievea level surface on the rail than would be the case were the pressureshift a gradual or progressive one.

Having thus described my invention, I claim:

1. A rail grinder of the class which includes a vehicle guided formovement along a rail, a grinding head having a drive motor and a rotarygrinding wheel below and driven by the said motor in operativeengagement with an upwardly presented portion of the rail to be ground,fluid pressure means for supporting a portion only of the weight of saidgrinder head from the vehicle, the balance of said weight constitutingthe operating pressure of the grinding wheel against the rail, saidfluid pressure means comprising an expansible chamber, the volume ofwhich varies with variations in the operating level of said grindinghead, and fluid in said chamber at a predetermined constant pressurewhen said grinding head is at a predetermined operating level withrespect to the rail being ground, the combination with said fluidpressure means of a pressure control unit communicating with saidexpansible chamber and responsive to deviation of said grinding headfrom its predetermined operating level for automatically changing thepressure of fluid in said chamber to and maintaining it at a newconstant pressure throughout any such deviation.

2. A rail grinder as defined in claim- 1, wherein said pressure controlmeans comprises a pressure reducing means for decreasing the fluidpressure in said chamber responsive to movement of the grinding heatabove said predetermined level.

3. A rail grinder as defined in claim 1, wherein said pressure controlmeans comprises a pressure increasing means for increasing the fluidpressure in said chamber responsive to movement of the grinding headbelow said predetermined level.

4. A rail grinder as defined in claim 1, wherein said pressure controlmeans comprises a pressure reducing means for decreasing the pressure insaid chamber when the grinding head moves above said predeterminedlevel, and a pressure increasing means for increasing the pres sure insaid chamber when the grinding head moves below said predeterminedlevel.

5. A rail grinder as defined in claim 1, wherein said pressure controlunit is formed to provide a two-diameter cylinder, a differential pistonbeing slidably disposed in said cylinder, stop means in said cylinderlimiting the movement of said piston into the small diameter end of thecylinder, means providing a normally closed path of communicationbetween said expansible chamber and one end of said cylinder, apredetermined quantity of liquid entrapped within and fully occupyingsaid chamber, said closed path and last mentioned end of said cylinder,said liquid being at a predetermined pressure for supporting apredetermined portion of the weight of said grinding head, when saidgrinding head is positioned at an optimum operating level with respectto the rail being ground, a source of fluid communicating with the otherend of said cylinder, and means for maintaining said fluid at a constantpressure substantially equal to said predetermined liquid pressure,whereby in the said predetermined position of the grinder head saiddifferential piston normally will be seated against said stop.

6. A rail grinder as defined in claim 5 including valve controlled meansfor temporarily interconnecting the said expansible chamber and saidsource of fluid for equalizing the pressures therein.

7. A rail grinder as defined in claim 1 wherein said pressure controlunit is formed to provide a two-diameter pressure reducing cylinder, adifferential piston being slidably disposed in each said cylinder, stopmeans in each cylinder limiting the movement of said pistons into thesmall diameter ends of the cylinders, means providing a normally closedpath of communication between said chamber and the small diameter end ofsaid pressure increasing cylinder and between said chamber and the largediameter end of said pressure reducing cylinder, a predeterminedquantity of liquid entrapped within and fully occupying said expansiblechamber, said closed path and the last mentioned ends of said controlcylinders, said liquid being at a predetermined pressure when both saidpistons seat against their respective stop means with said grinder headpositioned at its said predetermined operating level, a source of fluidcommunicating with the ends of the respective cylinders opposite totheir said first mentioned ends, and means for maintaining saidfluid ata constant pressure equal to said predetermined liquid pressure.

8. A rail grinder as defined in claim 7 including valve controlled meansfor equalizing the pressure of the liquid and fluid at the opposite endsof each cylinder when said grinding head is partially supported on therail at its predetermined operating level.

9. A rail grinder as defined in claim 8 in which said fluid is a gas andsaid means for maintaining the fluid at a constant pressure equal tosaid predetermined liquid pressure is a variable pressure regulator, apressurized source of gas communicating with said variable pressureregulator.

10. A rail grinder as defined in claim 1, wherein said pressure controlunit is formed to provide a two-diameter pressure increasing cylinderand a two-diameter pressure reducing cylinder, a differential pistonbeing slidably disposed in each said cylinder, stop means in eachcylinder limiting the movement of said piston into the small diameterends of the cylinders, means providing a normally closed path ofcommunication between said chamber and the small diameter end of saidpressure increasing cylinder and between said chamber and the largediameter end of 8 said pressure reducing cylinder, a predeterminedquantity of fluid entrapped within and fully occupying said expansiblechamber, said closed path and the last mentioned ends of said controlcylinders, said fluid being at a predetermined pressure when both saidpistons engage their respective stop means and said grinder head ispositioned at its predetermined operating level, a source of fluidcommunicating with the ends of said respective cylinders opposite tosaid first mentioned ends, and means for maintaining the fluid from saidsource at a constant pressure equal to said predetermined pressure,whereupon movement of the grinding head below its said predeterminedlevel will cause the opposing fluid pressures in said high pressurecontrol cylinder to displace the piston of 1 said cylinder into theenlarged end thereof to produce an increased constant fluid pressurewithin said expansible chamber to support an increased constant portionof the weight of said grinder head, and movement of the grinder headabove said level will permit the fluid of said predetermined constantpressure to transmit through the piston of its associated cylinder adecreased constant fluid pressure to said expansible chamber forsupporting a decreased constant portion of the weight of said grindinghead.

References Cited UNITED STATES PATENTS 2,197,729 4/1940 Miller 511782,779,141 1/1957 Speno et al. 5l178 3,358,406 12/1967 Speno et al.51-178 FOREIGN PATENTS 802,1 13 1958 Great Britain.

975,483 1964 Great Britain.

823,456 1949 Germany. 1,263,568 1960 France.

WILLIAM R. ARMSTRONG, Primary Examiner

